The long term objectives of this proposal are to investigate the mechanism(s) involved in airway smooth muscle cell proliferation induced by lysosomal hydrolases and to determine the contribution of lysosomal hydrolases in the pathogenesis of asthma. The overall hypothesis underlying this proposal is that lysosomal hydrolases promote hyperplasia/hypertrophy and subsequent airway hyperreactivity. The proposal is based on recent findings of a potent mitogenic action of mannosyl-rich glycoproteins including lysosomal hydrolases (beta-hexosaminidase A & B and beta-glucuronidase) on bovine airway smooth muscle cells. This mitogenic action is mediated by 175 kD mannose recognizing receptors (ASM-MR). Specific aims are: 1) To determine the contribution of p42 and p44 mitogen activated protein kinases (p42/44MAPK) and 70-kD ribosomal protein S6 kinase (p70S6k) in mannosyl-rich glycoprotein-induced mitogenesis in airway smooth muscle cells (ASMC). 2) To determine the contribution of p72Syk, and p125 focal adhesion kinase (p125FAK) in mannosyl-rich glycoprotein-induced mitogenesis in ASMC. 3) To investigate if airway smooth muscle mannose receptor (ASM-MR) and integrin(s) cooperate in transducing signal(s) in mannosyl-rich glycoprotein-induced mitogenesis. To accomplish specific aims 1 and 2, the activities of above kinases and cell proliferation in response to Hex and a mannosyl-rich neoglycoprotein in the presence and the absence of specific inhibitors, antisense-, sense-, and scrambled-oligonucleotides will be correlated. To accomplish specific aim 3, co-immunoprecipitation, cross linking analysis, immunocytochemistry, 35S-methionine metabolic labeling/immunoprecipitation analysis will be performed using specific antibodies to integrins that use the RGD recognition sequence. Integrin expression will be inhibited by multiple pulses of antisense-oligonucleotides and its effect will be examined in mannosyl-rich glycoprotein-induced mitogenesis. The proposed studies are intended to advance the knowledge of the mechanism(s) underlying airway smooth muscle proliferation.